Apparatus and system to actuate and pump well bore liquids from hydrocarbon wells

ABSTRACT

Pump apparatus and pump systems for use with hydrocarbon wells are actuated in response to a working fluid delivered at a high pressure to pump a fluid to be pumped or production fluid. The pump advantageously employs translation motion of a piston. Some embodiments employ working fluids at two ports. Other embodiments employ working fluid at one port and a spring. Working fluid may be provided via one or more hydraulically powered piston subassemblies, which may be controlled via one or more hydraulic power supplies. A flush system may include flush pump, flush valve and may be responsive to a characteristic of a fluid in a line.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national stage application filed under 35 U.S.C. §371 of International Patent Application PCT/US2010/024151, accorded an international filing date of Feb. 12, 2010, which claims benefit under 35 U.S.C. 119(e) to U.S. provisional patent application Ser. No. 61/154,263, filed Feb. 20, 2009, and entitled “Apparatus and System to Actuate and Pump Well Bore Liquids from Hydrocarbon Wells,” both of which are incorporated herein by reference in their entirety.

BACKGROUND

1. Technical Field

This application relates generally to down hole pumps for hydrocarbon wells, and more particularly to an extended life design to operate in high temperature environments and to pump abrasive silt-laden aqueous and/or chemically harsh well-bore liquid (“WBL”) from such wells.

2. Description of the Related Art

Hydrocarbon wells, particularly gas wells, having water and other liquids being produced at the same level in the formation as the desired produce need periodic de-watering because well-bore liquids (“WBL”) block free flow through the casing to the surface and interfere with evacuation of gaseous hydrocarbons rising from production zone. Such WBL typically take the form of a gaseous mixture of caustic water contaminated with oil, but may take other forms. Conventional downhole pumping systems include rotating parts (e.g., shafts and impellers) typically separated by polymer seals and in some cases driven by electrical motors that require insulated wires. Disadvantageously, these devices have a very limited life cycle when subjected to the abrasive and chemically harsh conditions encountered when de-watering well bores. Most of the devices are completely unsuitable for high temperature applications, such as steam assisted gravity drainage (SAGD) extraction of oil. Similarly, there are formations from which it is necessary to isolate different production zones accessible from a single well for either regulatory or contractual reasons.

BRIEF SUMMARY

According to the apparatus of the invention a dual-action sliding reciprocating piston non-rotating pump includes a continuous self-cleaning feature according to which each side of the production chamber is alternately flooded and evacuated in the reverse direction every half cycle thereby tending to resist silt build-up at either end of the production chamber or around the piston seals. Further, the continuous monitoring of the net flow of the system permits a PLC to trigger the clean water flushing of the pump body as needed by ejecting a very high (e.g. 5000 psi) pressure stream of flush water through both pressure chambers and the production chamber. In normal operation the low-speed high-volume piston moves smoothly alternating between the ends of its cycle pumping silt on every stroke in both directions so as to transfer silt-laden water up hole at a rate exceeding the installation's settling rate and thus keep any sediment in solution making it more efficient to pump out. Whenever the flow monitoring elements of the invented system detect a sufficient decrease in net flow between the pressure and production chambers, the PLC switches the system into flush mode and uses clean water from the surface to wash the inside of the pump under very high pressure returning any material, whether settled out or packed around the seals, to solution for evacuation from the pump. Whereas conventional pumps tend to last less than a year in service in these harsh conditions, advantageously the system of the invention permits this pumping apparatus to remain in service more than 2 years with minimal maintenance and less downtime. When applied to a normal temperature de-watering application the apparatus of the invention may be installed with urethane seals that handle abrasive solids and chemical attack very well. However, when applied to a very high temperature application such as SAGD oil pumping, the apparatus of the invention will preferably be installed with overlapping interlocking metal seals akin to the steel piston rings of a diesel engine.

Actuation of the pumping or output stroke of the apparatus of the invention occurs in 2 embodiments by fluid pressure (this fluid actuation subsystem charges each spring with potential energy) and in a 3^(rd) embodiment by spring pressure forcing liquids uphole, due to which modular design the stacking of spring subs permits the operator to amplify the lift of WBL for use in deeper wells.

Advantageously, the system of the invention operates for a significantly extended life cycle due to the combined effects of having: reduced and less aggressive movement and the elimination of rotating parts (e.g., no shafts or impellers) in the well bore, the related elimination of rubber or other polymer seals that would fail around rotating components, the elimination of electrical wires (e.g., power or control) having insulation that would melt, a nitride hardened interior pump bore, self-priming fluid actuated or assisted, and a self-flushing circuit. These design features result in a system that: is not affected by a high gas to oil ratio, has the ability to pump dry or in high sand cut installations, can operate horizontally, and can pump in high CO2 and H2S conditions as well as Light crude with aromatics. Advantageously the system of the present invention offers both longer life and less downtime (i.e., lower operating cost) but may still be installed at a lower capital cost.

Advantageously the system of the invention by pumping through tubes overcomes the problems associated with regulatory restrictions on co-mingling gas zones and the contractual requirements of separate ownership on shared wells producing from zones of different pressure, quality or value.

A pump suitable for hydrocarbon well applications may be summarized as including an elongated pump body having a first end and a second end opposite the first end, a first port at least proximate the first end and a second port at least proximate the second end, a central body portion between the first and the second ends and a pair of peripheral body portions between the central body portions and respective ones of the first and the second ends, the pump body forming a longitudinally extending pump body chamber extending between the first and the second ports, the first and the second ports providing fluid communication between the longitudinally extending pump body chamber and an exterior of the pump body, the longitudinally extending pump body chamber including a production chamber between the first and the second ends and a pair of pressure chambers between the production chamber and respective ones of the first and the second ends, the production chamber having a circumference that is larger than a circumference of either of the pressure chamber; and a piston having an elongated piston body including a first end and a second end opposite the first end, a central piston body portion between the first and the second ends and a pair of peripheral piston body portions between the central piston body portion and respective ones of the first and the second ends, the central piston body portion having an external circumference sized to be closely received by the production chamber of the pump body and the peripheral piston body portions each having a respective external circumference sized to be closely received by respective ones of the pressure chamber of the pump body, the piston body forming a passageway extending between and through the first and the second ends, the piston body slideably received in the longitudinally extending pump chamber of the pump body such that the central piston body portion divides the production chamber of the pump body into two production chamber portions, each of the production chamber portions having a volume that varies inversely with the volume of the other one of the production chamber portions, and the peripheral piston body portions received by respective ones of the pressure chambers of the pump body such that a respective volume of each of the pressure chambers of the pump body varies inversely with the volume of the other one of the pressure chamber.

The pump may further include a first seal, the first seal received about the circumference of the central piston body to form a seal with the production chamber portion; a second seal, the second seal received about the circumference of one of the peripheral piston body portions to form a seal with a respective one of the pressure chambers; and a third seal, the third seal received about the circumference of the other one of the peripheral piston body portions to form a seal with a respective one of the pressure chambers. The first, the second and the third seals may be urethane ring seals. The first, the second and the third seals are metal ring seals and the pump body chamber may be hardened. The pump body may include a third and a fourth port that provide fluid communication with respective ones of the production chamber portions from the exterior of the pump body to receive and expel fluid to be pumped, and wherein each of the peripheral piston body portions may include a piston head surface positioned in respective ones of the pressure chambers to be acted on by a working fluid introduced under pressure into the pressure chambers via the first and second ports to cause selective translation of the piston in the pump body chamber in two opposed directions.

The pump wherein the piston body forms a first production fluid port that provides fluid communication between the passageway of the piston body and the third port of the pump body and a second production fluid port that provides fluid communication between the passageway of the piston body and the fourth port of the pump body may further include a first valve received in the passageway of the piston body between the first end of the piston body and the third port of the pump body; and a second valve received in the passageway of the piston body between the second end of the piston body and the fourth port of the pump body.

The pump wherein the piston body forms a bypass channel may further include a flush valve received in the passageway of the piston body between the first and the second valves, the flush valve response to a much higher pressure than the first and the second valves.

The pump wherein the piston body forms a bypass channel may further include a first production screen coupled to the third port of the pump body; a first production valve coupled to control a fluid flow via the third port of the pump body; a second production screen coupled to the fourth port of the pump body; and a second production valve coupled to control a fluid flow via the fourth port of the pump body.

Each of the peripheral piston body portions may include a piston head surface, the piston head surface of a first one of the peripheral piston body portions positioned in a respective first one of the pressure chambers to be acted on by a working fluid introduced under pressure into the first one of the pressure chambers via the first port to cause selective translation of the piston in the pump body chamber in a first direction, and may further include a spring positioned to act on the piston head surface of the other one of the peripheral piston body portions to cause selective translation of the piston in the pump body chamber in a second direction opposite the first direction, wherein a fluid to be pumped is received in the pump body via the second port and is expelled from the pump body via the first port. The spring may move the piston in the second direction to a position at which the piston head surface of the first one of the peripheral piston body portions is adjacent the first outlet.

The pump may further include a first valve received in the passageway of the piston body between the first and the second ends of the piston body; and a check valve received in the passageway of the piston body between the first valve and the second end of the piston body, wherein the first valve and the check valve are cooperatively operable to selectively allow a fluid to be pumped to flow from the production chamber to the first pressure chamber without allowing a working fluid to flow from the first pressure chamber to the production chamber.

The pump may further include at least one spring sub removably physically coupled to the pump body and to the spring.

Each of the peripheral piston body portions may include a piston head surface, the piston head surface of a first one of the peripheral piston body portions positioned in a respective first one of the pressure chambers to be acted on by a working fluid introduced under pressure into the first one of the pressure chambers via the first port to cause selective translation of the piston in the pump body chamber in a first direction, and may further include a spring positioned to act on the piston head surface of the other one of the peripheral piston body portions to cause selective translation of the piston in the pump body chamber in a second direction opposite the first direction, wherein a fluid to be pumped is received in the pump body via the second port and is expelled from the pump body via a third port spaced distally from the second port with respect to the first port. The spring may move the piston in the second direction to a home position at which the piston head surface of the first one of the peripheral piston body portions is spaced from the first outlet.

The pump may further include a first valve that selectively controls a flow via the third port of the pump body; and a second valve that selectively controls a flow via the second port of the pump body, wherein the first and the second valves are cooperatively operable to selectively allow a fluid to be pumped to be received via the second port and expelled via the third port without allowing the fluid to be pumped to be expelled via the second port or received via the third port.

The pump may further include at least one spring sub removably physically coupled to the pump body and to the spring.

A pump system suitable for hydrocarbon well applications may be summarized as including a downhole pump apparatus selectively operable to pump a production fluid in response to a pressurized working fluid via translation of a piston; at least one hydraulically powered piston subassembly configured to alternately supply a working fluid at high pressure to actuate the downhole pump apparatus to pump a fluid to be pumped; at least one hydraulic power supply coupled to operate the at least one piston subassembly. The downhole pump apparatus may be a downhole pump apparatus according to any of claims 1 through 15.

The pump system may further include a flushing pump; and a flushing valve, the flushing pump and flushing valve configured to force a very high pressure stream of liquid through the downhole pump apparatus to flush any contaminants or any buildups out of the downhole pump apparatus.

The pump system may further include a sensor line to monitor a flow of fluid in a fluid line; and a controller configured to shutdown the at least one hydraulic power supply and to actuate the flushing pump to generate the very high pressure stream of liquid in response to a characteristic of the flow of fluid in the sensor line that is indicative of debris in the fluid flow. The controller may be configured to cause the very high pressure stream to exist the flush value in at least one of a steady state or in bursts. The at least one hydraulically powered piston subassembly may include two hydraulically powered piston subassemblies, each of the hydraulically powered piston subassemblies coupled a respective first and second working fluid ports of the downhole pump apparatus and configured to alternately supply a working fluid at high pressure to the first the second working fluid ports. The at least one hydraulic power supply may include two hydraulic power supplies, each of the hydraulic power supplies coupled to operate a respective one of the hydraulically powered piston subassemblies.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate preferred embodiments of the method, system, and apparatus according to the invention and, together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the drawings, identical reference numbers identify similar elements or acts. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not drawn to scale, and some of these elements are arbitrarily enlarged and positioned to improve drawing legibility. Further, the particular shapes of the elements as drawn, are not intended to convey any information regarding the actual shape of the particular elements, and have been solely selected for ease of recognition in the drawings.

FIG. 1 is a cut away isometric view of a pump apparatus that employs a double coil fluid actuated design, according to one illustrated embodiment.

FIG. 2 is an isometric partially broken view of a pump system including the pump apparatus of FIG. 1, configured for use dewatering the production zone of a gas lease by pumping well-bore liquids to the surface for disposal at a well site, according to one illustrated embodiment.

FIG. 3 is a cross-sectional view of a pump apparatus that employs a single coil spring actuated design, according to another illustrated embodiment.

FIG. 4 is cross-sectional broken view of the pump apparatus of FIG. 3 illustrating multiple spring subs (B and C) added to a basic pump body with spring sub A, according to yet another illustrated embodiment.

FIG. 5 is an schematic view of a pump system including the pump apparatus of FIG. 3, configured for use dewatering the production zone of a gas lease by pumping well-bore liquids to the surface for disposal at a well site, according to one embodiment.

FIG. 6 is a partial cross-sectional view of a pump apparatus that employs a single coil fluid actuated design, according to still another embodiment.

FIG. 7 is a broken cross-sectional view of the pump apparatus of FIG. 6, illustrating multiple spring subs (B and C) added to a basic pump body with spring sub A, according to yet still another embodiment.

FIG. 8 is a schematic diagram of a pump system including the pump apparatus of FIG. 6, configured for use dewatering the production zone of a gas lease by pumping well-bore liquids further downhole to a disposal zone at a well site, according to one illustrated embodiment.

DETAILED DESCRIPTION

In the following description, certain specific details are set forth in order to provide a thorough understanding of various disclosed embodiments. However, one skilled in the relevant art will recognize that embodiments may be practiced without one or more of these specific details, or with other methods, components, materials, etc. In other instances, well-known structures associated with wells, drilling equipment and pumping equipment have not been shown or described in detail to avoid unnecessarily obscuring descriptions of the embodiments.

Unless the context requires otherwise, throughout the specification and claims which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense, that is as “including, but not limited to.”

Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Further more, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise. It should also be noted that the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.

The headings and Abstract of the Disclosure provided herein are for convenience only and do not interpret the scope or meaning of the embodiments.

FIG. 1 shows an embodiment of a pump apparatus 100, according to one illustrated embodiment.

The pump apparatus 100 illustrated in FIG. 1 takes the form of a double coil-tube fluid actuated pumping device. The pumping device 100 has a body comprised of three segments, namely first and second peripheral pump bodies 110 and 120, respectively, and central pump body 130 interposed therebetween. The body includes an interior bore. The surface of the interior bore is preferably hardened by any suitable hardening treatment—e.g., nitride to 3000 Vicors.

The first and second peripheral pump bodies 110, 120 each form respective internal pressure chambers 118, 128, respectively. A coil tube connection 116 to an inlet/outlet port 115 and coil tube connection 126 to an inlet/outlet port 125 provides fluid access to the internal pressure chambers 118, 128, respectively. The central pump body 130 forms a production chamber 138. A double-ended piston assembly 131 is slidingly received in the production chamber 138. The double-ended piston assembly 131 includes a pair of peripheral ends 140, 160 and a central piston body 150 to which the peripheral ends 140, 160 are mechanically coupled. The central piston body has two opposed faces which form respective small piston heads 139 a, 139 b. Piston assembly 131 slidingly engages interior walls forming the chambers 118, 128, 138 of the respective pump body segments 110, 120, 130. Further, piston assembly 131 sealingly engages the interior of said chambers 118, 128, 138 with seals 147, 157 and 167. Thus, the double-ended piston assembly 131 divides the production chamber 138 into two production chamber portions 138 a, 138 b, respectively, each of production chamber portion 138 a, 138 b having a volume that varies inversely with the volume of the other production chamber portion 138 a, 138 b. Likewise, respective volumes of each of pressure chambers 118, 128 vary inversely with the volume of the other pressure chamber portion 118, 128.

Each of the peripheral ends 140, 160 of the double-ended piston assembly 131 includes a respective annular passage 145, 165, respectively. The annular passages 145, 165 permit well-bore liquid (“WBL”) to pass through the peripheral ends 140, 160 of the double-ended piston assembly 131 as the WBL moves between the two pressure chambers 118, 128 and the two production chamber portions 138 a, 138 b, respectively.

In summary, pump apparatus 100 alternately receives and expels WBL through each coil-tube 116 and 126. During a given pumping cycle, high pressure (e.g., typically 3000 psi) is applied to apparatus 100 through coil-tube 116 causing actuating liquid pumped from the surface to flow into pump apparatus 100 through inlet/outlet port 115 and coil-tube 116 while pressure is released from coil-tube 126 so as to permit production liquid to be expelled through inlet/outlet port 125 as the WBL in production chamber portion 138 b mixes with the WBL in pressure chamber 128 and a quantity of WBL evacuates to the surface.

More particularly, at the beginning of a pumping cycle WBL is delivered under high pressure (i.e., working fluid) through inlet/outlet port 115 to fill pressure chamber 118 and apply high pressure to small piston head 119 also filling passage 145 to close valve 170 whereupon piston assembly 131 slides away from inlet/outlet port 115 causing chambers 118 and 138 a to expand. As production chamber 138 a expands WBL (i.e., fluid to be pumped or production fluid) is drawn into pump apparatus 100 through a filter such as a screen 133 and valve 132 then passage 134 under relatively low pressure. The volume of such fluid is, according to the embodiment shown, greater than the volume of high-pressure fluid forced into pressure chamber 118. At the end of this stroke, central piston body 150 engages the opposing end of production chamber 138 so as to stop, with pump chamber 138 a substantially filled with WBL. Any fluid previously inside pressure chamber 128 and production chamber portion 138 b will of course be flushed out or expelled from pump apparatus 100 into coil-tube 126.

Commencing the second stroke of the two stroke pumping cycle, surface pressure is released from coil-tube 116 and WBL is delivered from the surface under high pressure (i.e., working fluid) through coil-tube 126 and inlet/outlet port 125 to fill pressure chamber 128 and apply high pressure to relatively small piston head 129 and fill passage 165 to close valve 180 whereupon piston assembly 131 slides away from inlet/outlet port 125 causing chambers 128 and 138 b to expand. As production chamber 138 b expands WBL (i.e., fluid to be pumped or production fluid) is drawn into pump apparatus 100 through screen 136 and valve 135 then passage 137 under relatively low pressure, while the mix of WBL in chambers 138 a and 118 is expelled from pump apparatus 100 through coil-tube 116 to the surface for processing and/or disposal.

Advantageously, the double acting design permits pump apparatus 100 to pump relatively efficiently in almost any conditions and installed at any angle of orientation whether vertical or horizontal or otherwise.

Advantageously, the low speed operation of piston assembly 131 sliding back and forth within central pump body 131 and the use of high-endurance (e.g., urethane) seals 147, 157, 167 permit pump apparatus 100 to survive the abrasive and chemically harsh downhole conditions typical of hydrocarbon wells for which de-watering of the production zone is required. However, to further enhance the operational lifespan, the pump apparatus 100 advantageously incorporates bypass channel 146 and very high pressure flush valve 190 (any suitable valve that does not open at all until a desired high operating pressure is applied (e.g., 5000 psi in certain applications) to piston assembly 131. At any point in the de-watering operation of a given well when the net production of WBL to the surface drops below a definable rate (as measured by surface borne flow rate meters not shown) for the formation in question, a system 200 (seen in FIG. 2) switches into a “flush mode.” In flush mode, piston assembly 131 is preferably moved to a home position and then a very high pressure (e.g., typically 5000 psi) stream of clean liquid (e.g., typically filtered surface water) is temporarily caused to flow down coil-tube 116 to wash (e.g., silt, compressed clay and other contaminants) out pressure chamber 118. The clean liquid then fills passage 145 and bypass channel 146 to force open very high pressure valve 190 as well as high pressure valve 180 and wash all contaminants in passage 165 out of pump apparatus 100 through coil-tube 126. The containments may be expelled to the surface where the system 200 (FIG. 2) monitors the condition (e.g., characteristic indicative of debris in the fluid flow) of the flushing stream until the flushing stream runs “clean” or otherwise meets definable criteria. A flushing subsystem provides for the resetting of the position of piston assembly 131 so as to repeat or pulse the flushing cycle and permit the flushing water (entrained with any suitable solvents if required) to clean the interior of at least one portion of the production chamber 138 so as to reach a major portion of the three pumping chambers 118, 128, 138 in the course of a given flushing cycle. According to an alternate embodiment, a very high pressure flush valve could also be installed (not shown) below valve 135 so as to permit back flushing to the formation through passage 137 in extremely silt-laden conditions.

According to an alternate embodiment of pump apparatus 100, the high-endurance seals 147, 157, 167 typically of urethane suitable for de-watering applications are replaced with overlapping steel or other suitable metal rings (similar to engine piston rings) that permit pump apparatus 100 to survive the very high-temperatures of SAGD operating near 340° C. while pumping heated oil.

FIG. 2 shows a pump system 200, according to one illustrated embodiment.

The pump system 200 is illustrated as installed in and around a well casing 210 perforated so as to harvest production flow 220 from which liquids drain into well sump 215 later to be pumped up-hole via double coil-tube assembly 230 and gaseous hydrocarbons rise up inside well casing 210 to supply a well head Christmas Tree 240 for collection in any suitable manner.

Double coil-tube assembly 230 comprises two coil-tubes 116, 126. According to a preferred embodiment, at least a portion of the coil-tubes 116, 126 are installed concentric one to another. The surface coil-tube 126 delivers WBL to line 238 whereas coil-tube 116 delivers WBL to line 235. Hydraulically powered piston subassemblies 250/257 and 260/267 alternately supply high pressure (e.g., 3000 psi) to coil-tubes 116, 126 respectively to actuate pump apparatus 100. Any suitable hydraulic power supplies 255 and 265 are used to operate piston subassemblies 250/257 and 260/267 together with any suitable hydraulic switching control and line assembly 280.

Advantageously, after relieving the pressure on piston subassembly 260/267, flushing valve 275 may be used in conjunction any suitable supply of clean liquid (not shown) and flushing pump 270 (any suitable pump such as a CAT® pump) to force a very high pressure stream liquid through pump apparatus 100 so as to flush contaminants and any build-up of compressed clay or abrasives out of the pump apparatus 100 and up coil-tube 126 for surface disposal. The sensor line 272 is used to monitor the flow in lines 235 and 238 so as to determine when silt constriction of pump apparatus 100 has reached a level that requires flushing. Any suitable programmable logic controller (PLC) or other controller (e.g., microprocessor, programmable gate array, digital signal processor,) and flow metering circuitry may be used to set the flushing sub-system parameters so as to trigger the shutdown of hydraulic power supplies 255 and 265, together with switching control and line assembly 280, while engaging flushing pump 270 to generate very high pressure either at steady state or in bursts through flush valve 275.

FIG. 3 shows a pump apparatus denoted generally as 300, according to another illustrated embodiment.

The pump apparatus 300 takes the form of a single-coil spring actuated pump apparatus. Pump body 310 is fluidly coupled to single coil-tube 316 via inlet/outlet port 315 to supply a fluid (i.e., working fluid), typically a WBL, under high pressure into pressure chamber 318. The WBL pumped downhole into pressure chamber 318 acts on the head 319 of piston assembly 320. Piston assembly 320 is comprised of a small piston top 321, larger piston head 325, and piston shaft 340 within which piston annulus 322 is in fluid communication with pressure chamber 318. On each intake stroke, WBL inside piston annulus 322 applies a relatively high pressure to keep valve 330 closed while WBL (i.e., fluid to be pumped or production fluid) from the production zone (not shown) enters pump apparatus 300 through inlet port 385A at the downhole end of spring sub 360A which the WBL enters under the relatively low pressure of the surrounding formation flooding through piston intake passages 347 and thereafter rising through piston lower annulus 345 and check valve 335 to fill production chamber 328 through piston fluid exchange passages 327. The downhole end of spring sub 360A may be removeably coupled to pump bottom 350 by any suitable coupling structure, for example threads. As piston assembly 320 moves to the bottom of its intake stroke, spring 370A compresses and production chamber 328 expands and fills with WBL. At the end of this intake stroke the surface pressure source (not shown but similar to hydraulic power supply 255) switches to release the pressure previously applied on piston head 319 through coil tube 316, whereupon the output or pumping stroke commences with spring 370A releasing its charge of potential energy to force piston assembly 320 towards its home position, simultaneously expelling the WBL contents of production chamber 328 through piston fluid exchange passages 327 then valve 330 and up piston annulus 322 to combine with the WBL already then in pressure chamber 318. The blend of which WBL is expelled up-hole through coil-tube 316 for surface disposal.

FIG. 4 shows a pump apparatus denoted generally as 400, according to another illustrated embodiment.

The pump apparatus 400 is similar to the pump apparatus 300 shown in FIG. 3, but includes a number of extending spring subs added thereto. The basic pump body 310 has been physically coupled (e.g., threaded) to a first actuating spring sub 360A in order to permit apparatus 300 to function as a pump returning WBL to the surface from shallow wells. Apparatus 400 is formed by adding spring sub 360B and spring sub 360C so as to permit pumping from slightly deeper wells. A person of skill in the art of spring actuated pumping would understand that multiplying the potential energy stored when the springs are compressed during the down or intake stroke—by increasing the number of springs so compressed—enables apparatus 400 to overcome the greater head pressure associated with deeper well applications. Further, each spring sub 360B and 360C mechanically and fluidly connects to the spring sub positioned relatively above it. According to the embodiment illustrated in FIG. 4, spring sub 360B threads into base 375A, and spring sub 360C threads into base 375B, but it is to be understood that subs may be added in series by any suitable connection.

Similar elements are numbered similarly, and will not be specifically called out in the description in the interest of clarity and brevity.

FIG. 5 shows a pump system denoted generally as 500, according to another illustrated embodiment.

The pump system 500 may include apparatus 300 of FIG. 3, configured for use de-watering production zone 410 of a gas lease by pumping well-bore liquids to the surface for disposal. It is to be understood that gas well de-watering is but one of the down hole applications for which system 500 is suitable. Pump apparatus 300 may be configured for high temperature operation and for the pumping of liquids (e.g., oil or mixtures having a high “sand cut”) other than water and hence suitable for applications other than those WBL pumping applications previously described. However, as illustrated, pump apparatus 300 is lowered through well casing 505 into production zone 510 where WBL stream 515 enters apparatus 300 through spring sub 360A and is pumped to the surface through coil-tube 316 in the manner described above in reference to FIG. 3. Upon reaching the surface, WBL stream 515 enters fluid exchange lines 530 where the WBL stream passes to reservoir 540 from which excess WBL may be either processed or disposed of via system outflow line 545. Power source 540 is any suitable engine, pump and valve combination for controlling flow and pressure between coil-tube 316 and outflow line 545. A preferred embodiment of a power source 540 is the hydraulic pumping system 200 (FIG. 2). With the WBL stream 515 evacuated from well casing 505, gaseous flow 520 rises through well casing 505 past pump apparatus 300 to be harvested at well-head Christmas Tree 240 (called out in FIG. 2, not called out in FIG. 5) as production flow 525.

FIG. 6 shows a pump apparatus denoted generally as 600, according to yet another illustrated embodiment.

The pump apparatus 600 takes the form of a single-coil fluid actuated pump apparatus. Pump body 610 is fluidly coupled to single coil-tube 316 via inlet/outlet port 315 to supply a suitable fluid under high pressure (i.e., working fluid) into pressure chamber 618. Since the fluids in pressure chamber 618 and production chamber 638 never mix, according to this embodiment any clean fluid (e.g., hydraulic oil) may be used as stream 617 to actuate pump apparatus 600. Further, while the embodiment of FIG. 3 uses spring 370A to pump fluid up-hole, spring 670A of apparatus 600 is only used to return piston assembly 620 to a home position during which upstroke pump body 660 draws WBL (i.e., fluid to be pumped or production fluid) inside production chamber 638 from production zone 810 (see FIG. 8). It is the subsequent delivery of surface fluid—as pressure stream 617 to pressure chamber 618 that applies pressure to piston head 619 forcing piston assembly 620 downward—that actuates the pumping or output stroke during which WBL is expelled downward to disposal zone 830 (FIG. 8), rather than to the surface, at a location lower in the formation below production zone 810.

As upper piston assembly 620 slides inside of pump body 610, piston extension shaft 630 passes through pump bottom 350 and into spring sub 360A to engage sub shaft 645A and compress spring 670A thereby charging it with potential energy. Sub shaft 645A in turn engages lower piston shaft 650 causing lower piston 655 to slide inside lower pump body 660. As lower piston 655 moves downward under the pressure of fluid stream 617 the WBL contents of production chamber 638 are expelled through passage 672 and valve 675 and then passage 671 passing through packer 690 and outgoing fluid stream 695 injected into the formation below packer 690. Packer 690 is fluidly and mechanically coupled to lower pump body 670 by any suitable tube and fluid coupling sub-assembly 697. With sub spring 670A fully charged at the bottom of the previously described pumping or output stroke, the pressure at the surface is released and fluid stream 617 flows back up-hole through coil-tube 316 causing pressure chamber 618 to empty as spring 670A returns upper piston assembly 620 to its home position—simultaneously causing lower piston 655 to move upward and draw new WBL into production chamber 638 as low pressure stream 685 through inlet passage 682 opening valve 680 so as to flood through passage 672 into production chamber 638. Once spring 670A is fully extended and relaxed lower piston 655 is at the top of its intake stroke, the cycle repeats.

FIG. 7 shows a pump apparatus denoted generally as 700, according to still another illustrated embodiment.

The pump apparatus 700 is similar to the pump apparatus 600 (FIG. 6) but includes a number of extending spring subs added thereto. Basic pump body 610 has been physically coupled (e.g., threaded) to a first spring sub 360A. The first spring sub 360A has in turn been physically coupled (e.g., threaded) to a second spring sub 360B. The second spring sub 360B has in turn been physically coupled (e.g., threaded) to lower pump body 660. Lower pump body 660 has in turn been coupled to packer 690—all in order to permit pump apparatus 700 to function as a pump. It is to be understood that dummy subs (i.e., subs having no springs) may also be added in series via any suitable connection structure so as to increase a length of pump apparatus 700, if needed or desired. Further, in the event that a distance between the production zone inlet stream 685 and the bottom of packer 690 needs to be increased for a given formation, the length of tube and fluid coupling sub-assembly 697 may be increased.

FIG. 8 shows a pump system denoted generally as 800, according to yet still another illustrated embodiment.

The pump system 600 includes pump apparatus 600 (FIG. 6), and is shown configured for use de-watering production zone 810 of a gas lease by pumping well-bore liquids downward to disposal zone 830. It is to be understood that gas well de-watering is but one of the down hole applications for which system 800 is suitable. Since pump apparatus 600 may be configured for high temperature operation and/or for the pumping of liquids (e.g., hot oil or mixtures having a high “sand cut”) other than water, the system 800 may be used for applications other than the WBL pumping applications previously described. No WBL from production zone 810 is delivered to the surface, but the WBL is instead expelled downward into the disposal zone 830. Pump apparatus 600 operates within casing 805 that has been perforated at the level of production zone 810, but then extends deeper through the formation into disposal zone 830 where WBLs may be disposed of without the need to bring the WBLs to the surface. Pump apparatus 600 is lowered inside casing 805 to a formation level where screen (not shown) is exposed to the WBL in production zone 810 and packer 690 is placed below the level of production zone 810 so as to seal casing 805 and prevent fluid exchange between production zone 810 and disposal zone 830.

Assisted by one or more springs 370 (not shown in FIG. 8), pump apparatus 600 is filled with WBL from production zone 810 in the manner described above with reference to FIG. 6. Thereafter WBL streams 685 and 695 are respectively drained and expelled from well casing 805, such that gaseous flow 820 rises through well casing 805 past pump apparatus 600 to be harvested at well-head Christmas Tree 240 (not called out in FIG. 8) as production flow 825. Fluid stream 617 simply flows back and forth through coil-tube 316 between reservoir 840 and pressure chamber 618 (not called out in FIG. 8) periodically actuating the pumping stroke of pump apparatus 600. Power source 850 and reservoir 840 are any suitable engine, pump and valve combination a preferred embodiment of which is based on hydraulic pumping system 200 (FIG. 2).

Although the disclosure describes and illustrates various embodiments of the invention, it is to be understood that the invention is not limited to these particular embodiments. Many variations and modifications will now occur to those skilled in the art of hydrocarbon well de-watering and high temperature pumping. For example, the various embodiments described may be combined to provider further embodiments. These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure. 

1. A pump suitable for hydrocarbon well applications, the pump comprising: an elongated pump body having a first end and a second end opposite the first end, a first port at least proximate the first end and a second port at least proximate the second end, a central body portion between the first and the second ends and a pair of peripheral body portions between the central body portions and respective ones of the first and the second ends, the pump body forming a longitudinally extending pump body chamber extending between the first and the second ports, the first and the second ports providing fluid communication between the longitudinally extending pump body chamber and an exterior of the pump body, the longitudinally extending pump body chamber including a production chamber between the first and the second ends and a pair of pressure chambers between the production chamber and respective ones of the first and the second ends, the production chamber having a circumference that is larger than a circumference of either of the pressure chamber; and a piston having an elongated piston body including a first end and a second end opposite the first end, a central piston body portion between the first and the second ends and a pair of peripheral piston body portions between the central piston body portion and respective ones of the first and the second ends, the central piston body portion having an external circumference sized to be closely received by the production chamber of the pump body and the peripheral piston body portions each having a respective external circumference sized to be closely received by respective ones of the pressure chamber of the pump body, the piston body forming a passageway extending between and through the first and the second ends, the piston body slideably received in the longitudinally extending pump chamber of the pump body such that the central piston body portion divides the production chamber of the pump body into two production chamber portions, each of the production chamber portions having a volume that varies inversely with the volume of the other one of the production chamber portions, and the peripheral piston body portions received by respective ones of the pressure chambers of the pump body such that a respective volume of each of the pressure chambers of the pump body varies inversely with the volume of the other one of the pressure chamber.
 2. The pump of claim 1, further comprising: a first seal, the first seal received about the circumference of the central piston body to form a seal with the production chamber portion; a second seal, the second seal received about the circumference of one of the peripheral piston body portions to form a seal with a respective one of the pressure chambers; and a third seal, the third seal received about the circumference of the other one of the peripheral piston body portions to form a seal with a respective one of the pressure chambers.
 3. The pump of claim 2 wherein the first, the second and the third seals are urethane ring seals.
 4. The pump of claim 2 wherein the first, the second and the third seals are metal ring seals and the pump body chamber is hardened.
 5. The pump of claim 1 wherein the pump body includes a third and a fourth port that provide fluid communication with respective ones of the production chamber portions from the exterior of the pump body to receive and expel fluid to be pumped, and wherein each of the peripheral piston body portions includes a piston head surface positioned in respective ones of the pressure chambers to be acted on by a working fluid introduced under pressure into the pressure chambers via the first and second ports to cause selective translation of the piston in the pump body chamber in two opposed directions.
 6. The pump of claim 5 wherein the piston body forms a first production fluid port that provides fluid communication between the passageway of the piston body and the third port of the pump body and a second production fluid port that provides fluid communication between the passageway of the piston body and the fourth port of the pump body, further comprising: a first valve received in the passageway of the piston body between the first end of the piston body and the third port of the pump body; and a second valve received in the passageway of the piston body between the second end of the piston body and the fourth port of the pump body.
 7. The pump of claim 6 wherein the piston body forms a bypass channel, further comprising: a flush valve received in the passageway of the piston body between the first and the second valves, the flush valve response to a much higher pressure than the first and the second valves.
 8. The pump of claim 6 wherein the piston body forms a bypass channel, further comprising: a first production screen coupled to the third port of the pump body; a first production valve coupled to control a fluid flow via the third port of the pump body; a second production screen coupled to the fourth port of the pump body; and a second production valve coupled to control a fluid flow via the fourth port of the pump body.
 9. The pump of claim 1 wherein each of the peripheral piston body portions includes a piston head surface, the piston head surface of a first one of the peripheral piston body portions positioned in a respective first one of the pressure chambers to be acted on by a working fluid introduced under pressure into the first one of the pressure chambers via the first port to cause selective translation of the piston in the pump body chamber in a first direction, and further comprising: a spring positioned to act on the piston head surface of the other one of the peripheral piston body portions to cause selective translation of the piston in the pump body chamber in a second direction opposite the first direction, wherein a fluid to be pumped is received in the pump body via the second port and is expelled from the pump body via the first port.
 10. The pump of claim 9 wherein the spring moves the piston in the second direction to a position at which the piston head surface of the first one of the peripheral piston body portions is adjacent the first outlet.
 11. The pump of claim 9, further comprising: a first valve received in the passageway of the piston body between the first and the second ends of the piston body; and a check valve received in the passageway of the piston body between the first valve and the second end of the piston body, wherein the first valve and the check valve are cooperatively operable to selectively allow a fluid to be pumped to flow from the production chamber to the first pressure chamber without allowing a working fluid to flow from the first pressure chamber to the production chamber.
 12. The pump of claim 9, further comprising: at least one spring sub removably physically coupled to the pump body and to the spring.
 13. The pump of claim 1 wherein each of the peripheral piston body portions includes a piston head surface, the piston head surface of a first one of the peripheral piston body portions positioned in a respective first one of the pressure chambers to be acted on by a working fluid introduced under pressure into the first one of the pressure chambers via the first port to cause selective translation of the piston in the pump body chamber in a first direction, and further comprising: a spring positioned to act on the piston head surface of the other one of the peripheral piston body portions to cause selective translation of the piston in the pump body chamber in a second direction opposite the first direction, wherein a fluid to be pumped is received in the pump body via the second port and is expelled from the pump body via a third port spaced distally from the second port with respect to the first port.
 14. The pump of claim 13 wherein the spring moves the piston in the second direction to a home position at which the piston head surface of the first one of the peripheral piston body portions is spaced from the first outlet.
 15. The pump of claim 13, further comprising: a first valve that selectively controls a flow via the third port of the pump body; and a second valve that selectively controls a flow via the second port of the pump body, wherein the first and the second valves are cooperatively operable to selectively allow a fluid to be pumped to be received via the second port and expelled via the third port without allowing the fluid to be pumped to be expelled via the second port or received via the third port.
 16. The pump of claim 13, further comprising: at least one spring sub removably physically coupled to the pump body and to the spring.
 17. A pump system suitable for hydrocarbon well applications, the pump system comprising: a downhole pump apparatus selectively operable to pump a production fluid in response to a pressurized working fluid via translation of a piston; at least one hydraulically powered piston subassembly configured to alternately supply a working fluid at high pressure to actuate the downhole pump apparatus to pump a fluid to be pumped; at least one hydraulic power supply coupled to operate the at least one piston subassembly.
 18. The pump system of claim 17 wherein the downhole pump apparatus is a downhole pump apparatus according to any of claims 1 through
 16. 19. The pump system of claim 17, further comprising: a flushing pump; and a flushing valve, the flushing pump and flushing valve configured to force a very high pressure stream of liquid through the downhole pump apparatus to flush any contaminants or any buildups out of the downhole pump apparatus.
 20. The pump system of claim 19, further comprising: a sensor line to monitor a flow of fluid in a fluid line; and a controller configured to shutdown the at least one hydraulic power supply and to actuate the flushing pump to generate the very high pressure stream of liquid in response to a characteristic of the flow of fluid in the sensor line that is indicative of debris in the fluid flow.
 21. The pump system of claim 20 wherein the controller is configured to cause the very high pressure stream to exist the flush value in at least one of a steady state or in bursts.
 22. The pump system of claim 17 wherein the at least one hydraulically powered piston subassembly includes two hydraulically powered piston subassemblies, each of the hydraulically powered piston subassemblies coupled a respective first and second working fluid ports of the downhole pump apparatus and configured to alternately supply a working fluid at high pressure to the first the second working fluid ports.
 23. The pump system of claim 22 wherein the at least one hydraulic power supply includes two hydraulic power supplies, each of the hydraulic power supplies coupled to operate a respective one of the hydraulically powered piston subassemblies. 